Gov. Herbert, a Republican, has not made it clear whether he will sign the bill into law or veto it.

"If those substances cannot be obtained, this proposal would make sure that those instructed to carry out the lawful order of the court and the carefully deliberated decision of the jury can do so," he said.

"Our state, as is the case with states around the country, is finding it increasingly difficult to obtain the substances required to perform a lethal injection.

"We are dedicated to pursuing all reasonable and legal options to obtain those substances to make sure that, when required, we are in a position to carry out this very serious sentence by lethal injection."

A 2010 file photo shows the firing squad execution chamber at the Utah State Prison in Draper, Utah

State congressman Paul Ray authored and sponsored the bill, citing firing squad as the next most humane death penalty.

"Any form of death is obviously a serious subject, so the two reasons I chose it were, obviously, No. 1, that’s what we’ve done in the past, and secondly, out of all the other options, it is the most humane," Ray told the Los Angeles Times.

Gardner apparently chose firing squad because he hoped it would stir up controversy and a debate about capital punishment.

If Rep. Ray's bill is signed into law, prisoners will not have the choice, firing squads will be used by default if the appropriate lethal injection drugs cannot be secured 30 days before the scheduled execution date.

"It's not humane at all," Gardner's brother Randy told NBC. "I got to see the four bullet wounds in my brother's chest after the execution and I could have put my hand in there. It's cruel and unusual punishment for sure."